Dietel M, Hölzel F, Arps H, Bressel M
Acta Endocrinol (Copenh). 1984 Nov;107(3):375-81. doi: 10.1530/acta.0.1070375.
In vitro parathyroid hormone secretion of normal (n = 10) and adenomatous (n = 20) human parathyroid glands was compared in response to different calcium (Ca++) concentrations. The glands, prepared for tissue culture immediately after surgical removal, were incubated under identical conditions for 6 h. The medium was changed hourly and analyzed for PTH and cAMP using radioimmunoassay. During the first 2 h of the experiment, the Ca++ concentrations of all preparations was kept constant at 1.2 mM equivalent to the normal Ca++ level of the intercellular space. The PTH level of the 2nd h was defined as reference value corresponding to 100%. After the 2nd h of incubation the Ca++ concentration in the medium was shifted either to low (0.9 or 0.6 mM) or to high (1.9 or 2.6 mM) values. In low Ca++ concentrations (0.6 mM) the normal parathyroid glands responded by stimulation of the PTH release up to 310% in relation to the reference value, whereas the adenomas enhanced the PTH release to 160% only. The incubations in 0.9 mM Ca++ resulted in a slightly lower degree of stimulation. During the incubation in high Ca++ the PTH secretion was reduced to 28% by normal glands and to 52% by adenomatous parathyroid glands. Movements of cAMP measurements paralleled PTH values. The study provides evidence for an abnormally low responsiveness of parathyroid adenomas to Ca++ when compared with normal glands. The reduction in Ca++ responsiveness of adenomatous cells appears to have a fundamental role in primary hyperparathyroidism since the tumour cells may obviously recognize normal Ca++ levels as 'hypocalcaemic' and react by a stimulated PTH secretion.
比较了正常（n = 10）和腺瘤性（n = 20）人甲状旁腺在不同钙（Ca++）浓度下的体外甲状旁腺激素分泌情况。这些腺体在手术切除后立即准备用于组织培养，并在相同条件下孵育6小时。每小时更换培养基，并使用放射免疫测定法分析其中的甲状旁腺激素（PTH）和环磷酸腺苷（cAMP）。在实验的前2小时，所有制剂的Ca++浓度保持恒定在1.2 mM，相当于细胞间空间的正常Ca++水平。将第2小时的PTH水平定义为对应于100%的参考值。在孵育2小时后，将培养基中的Ca++浓度转移至低水平（0.9或0.6 mM）或高水平（1.9或2.6 mM）。在低Ca++浓度（0.6 mM）下，正常甲状旁腺通过刺激PTH释放，相对于参考值可高达310%，而腺瘤仅将PTH释放增强至160%。在0.9 mM Ca++中孵育导致刺激程度略低。在高Ca++孵育期间，正常腺体的PTH分泌降至28%，腺瘤性甲状旁腺腺体降至52%。cAMP测量值的变化与PTH值平行。该研究提供了证据，表明与正常腺体相比，甲状旁腺腺瘤对Ca++的反应异常低。腺瘤细胞Ca++反应性的降低似乎在原发性甲状旁腺功能亢进中起基本作用，因为肿瘤细胞显然可能将正常Ca++水平识别为“低钙血症”，并通过刺激PTH分泌做出反应。
